COMBINED MOTORIZATION TRAINING/ TEST AIRCRAFT

HISTORY

Program's genesis

By the end of World War II, the French Air Force flew a motley fleet of transport aircraft which was not fitted to carry heavy loads. Various projects were launched, including the NC.211 Cormoran, a four-engined plane able to carry up to 13 tons on a range of 1,000 km. Unfortunately, it was cancelled in 1950.
In the same period, in 1947, the Direction Technique Industrielle (Industrial Technical Office) released specifications based on studies for a middle weight aircraft which's new conception allowed for an easy use. The Société Nationale de Construction Aéronautique du Nord (National Corporation of Northern Aeronautical Construction) with the Nord 2500 and Breguet with the Br.891R Mars fulfilled those requirements. At the same time, the SNCASO (Société Nationale de Construction Aéronautique du Sud-Ouest/ National Corporation of South Western Aeronautical Construction) offered the SO.30C. .
Jean Calvy, a SNCAN's engineer, came up with a combination for a high-wing airframe with two booms around a central fuselage with a clamshell opening at it's rear. It would be powered by two Gnôme-et-Rhône 14R, 1.600 hp engines, fitted with 3 blade variable pitch propellers.
On April 27th 1948, the DTI asked the SNCAN to build 2 prototypes. The first one was built at the Issy-les-Moulineaux factory, then taken apart and shipped to Melun-Villaroche where it was assembled and checked. It made it's first flight on September 10th 1949 in the hands of Claude Chautemps and Georges Détré.

It was decided to power the second prototype with English Bristol Hercules type 739 engines, developing 2,040 hp on takeoff, to which Rotol four blade props were fitted. From then on it was designated Nord 2501. This prototype crashed on July 6th 1952 at Lyon-Bron, killing all five people aboard, including famous female aviator Maryse Bastié. The selection eventually designated the Nord 2501. The first order was placed on July 10th 1951, and the first production aircraft flew on November 24th 1952, in the hands of Georges Détré. Not until early 1953 was the plane dubbed Noratlas. 426 aircraft of all versions were eventually produced, including 8 prototypes and 3 pre-production aircraft. While the SNCAN factory at Les Mureaux manufactured the booms and tails, the factory at Bourges made the fuselage. Breguet manufactured the wings and, under licensing, the Rotol propellers. SNECMA also had a licence for the Hercules 738 and 739 engines. Initially the final assembly took place at either Les Mureaux or Bourges, at the end only Bourges did it.

A sole example in service within the Aéronautique Navale during 27 years

Concept
The story of the N.2504 in the French Navy started with a need, in the 1950s, for a new heavy, multi-engine ASW and patrol aircraft. This was also the period which saw the success of the Nord 2501 Noratlas, which first flew on September 10th 1949, and of which 400+ were built. The Noratlas was thus a natural contender, and the Navy tested it and found it solid and resistant, and especially appreciated its important payload.
Faced with the Navy's requirements, Nord first offered a simple ASW version of the N.2502, but it was quickly abandoned, due to the strong competition : Breguet 754, Hurl Dubois 35 and Bloch 161. Eventually the Navy favoured the P2V-6 Neptune. The N.2502 was one of many derivatives from the 2501, and was originally built for civilian companies operating from Africa, which needed aircraft capable of short takeoffs in hot weather. It was therefor fitted with either Marboré II or RAMA II 400 kg turbojets on both wingtips.
The Navy was nevertheless very impressed by this airframe, and asked Nord to study a training version based on the ASW N.2502. This new version was called N.2504, and was finally ordered : order n° 3229/57 was for a full scale mock-up and a prototype ; value of the contract was 530 million Frs. The contract also specified that the pane was to fly before December 31st 1958.
The full scale wooden mock-up was built at Châtillon-sous-Bagneux, and shortly after that the prototype was assembled at the S.N.C.A.N. factory. The airframe is identical ti that of the 2502, and the interior is up to date with Navy requirements.
Prototype N.2504 n°01 finally flew on November 17 1958 from the Melun-Villaroche airfield with Jean Caillaud in the cockpit. After a brief stay at the C.E.V. (Flight Test Center), the prototype was taken over by the C.E.P.A. (Navy Test and Evaluation Center) on June 24th 1959, flown by Arland Jacquet ; by then the plane had already flown 85 hours. The 1957 budget had announced for 5 aircraft, but financial difficulties saw this order cancelled ; the prototype will be the only N.2504 ever delivered to the Navy, which will assign it to flight 10.S.

Compared to the Nord 2501 Noratlas, the 2504 (just like the 2502) had 2 Turboméca Marboré II 400 kg turbojets. Fitted on the wingtips, they used piston engine fuel, and like the J-34 that equipped the P2V-7, had built in intake covers (to protect them from salt water) that opened only when the engine was working. The wing was also strengthened and fitted with 6 hardpoints, each capable of 200 kg loads.

In unit
Since the airplane also was also supposed to serve as a flying testbed, it was assigned to flight 10.S at N.A.S. Fréjus Saint-Raphaël, the Navy's unit in charge with tests and experiments.

On December 2nd 1959, the Nord 2504 was one of the only survivors of the Malpasset tragedy : a damn broke and flooded the valley - and the base. Most aircraft were lost but the Noratlas survived by miracle. Within flight 10.S, the plane had two main missions : ASW and maritime patrol (PATMAR) training, and especially avionics and equipment testing.

Training missions
For these missions the airframe was entirely transformed into a schoolroom. Not only did it receive an entire ASW suit (double sonobuoy launcher, dinghy, retractable radar antenna), but the cargo bay was fitted with enough tables and seats for one instructor and 16 students. Such missions could last up to several hours, and replicate the exact conditions of ASW or PATMAR missions.

The testing and evaluation mission
As a testbed, the Nord 2504 was fitted with many different avionics systems, antennae and probes.

This equipment was powered by a Gevaudan auxiliary power unit located on the right side of the fuselage, just below the wing. The airplane was officially retired from active service by the Navy on august 1st 1987, having by then flown 6,850 hours. Its last flight took place on June 26th 1988 when it was flown to the Aix-le-Milles airfield and handed over to the " Pégase " association. For this last flight pilots were VAE Doniol (head of Naval Aviation Central Services) and CF Astraud.

CHARACTERISTICS	(US)	(FR)
LENGTH	110. 2 ft	33. 6 m
WINGSPAN	72 ft	21. 97 m
HEIGHT	21. 6 ft	6. 60 m
WEIGHT	50 706 lb (max)	23 000 kg (max)
CRUISE SPEED	167. 7 mph	270 km/h
MAX RANGE	615. 5 nm	1 140 km
CEILING	22 965 ft	7 000 m
POWER	4 000 hp	2 982 kW

MISCELLANEOUS

The crew includes three people.

MOTORIZATION

-Two Bristol Hercules 791 of 2.000 hp each. -Two Turboméca Marboré II jet engines of 400 kg each.

PHOTO GALLERY WALK-AROUND

sources - acknowledgements :
Amiral Guirec Doniol, chef du Service Central de l'Aéronautique Navale en 1986-1989.
Louis Rogelet
Hervé Brun
Pierre Pecastaingts
www.cocardes.com
www.aviation-fr.info